The fact that this is probably the third design submitted to the challenge makes me think that you've been sitting on this idea for months—maybe years—quietly thinking to yourself, "Someday, perhaps years from now, all Threadless designers will be called upon to design a truly iconic tee. And when that day comes, I, Montro, WILL BE READY!"

first of all, how did you get so many people to commit on this?
2nd, It seems that everyone loves it so, don't listen to my critique.
It looks weird that the astronaut is not on the other side of the bar, because he is squeezed between the keys. I guess he's sitting on the keys, but those keys are on the same plane as the space bar.
Maybe try a shadow on the other keys cast by his body.
Also, this is freak'n brilliant. He's not planning to fly now after all them drinks is he?

Love the concept, and it's a great execution, but I would suggest giving a little bit of perspective to the keyboard, the way it looks right now from a distance is a big slab of white, so maybe that would help on a aestethic level :)